1. Field of the Invention
This invention relates to burner units to simulate burning in a traditional fireplace and more particularly to units which may be operated in a non-vented dwelling space.
2. Prior Art
Since at least colonial times the fireplace has been a source of heat during cold weather and for cooking. Typically, wood or coal is burned with the products of combustion vented outside by a chimney.
The Franklin stove, invented by Benjamin Franklin in the late 1700's, provided a vastly improved heat source because a greater percentage of the generated heat transferred to the space in which the stove was located while a lesser percentage vented to the outside.
While in most modern dwellings the fireplace is no longer the primary source of heat, an open flame in a living space remains a pleasurable experience for its aesthetic and physiological effects. As such, a number of substitute structures have been suggested to improve heat transfer and eliminate the need for the traditional masonry chimney. U.S. Pat. Nos. 1,867,740, 3,636,307 and 3,742,189 set forth electrical energized heating units with open burning simulation created by a flow of air and light directed through defusing materials.
A structure which provides improved heat transfer is set forth in U.S. Pat. No. 2,134,935 where self-contained ducting is used to transfer heat to room air circulating in the ducting. In U.S. Pat. No. 3,533,394 the products of combustion from a gas log in a fire box are discharged externally by an exhaust fan. This fan also circulates room air in duct work about the fire box. U.S. Pat. No. 3,654,913 discloses a gas fueled fireplace with artificial logs. Heat is generated in a sealed chamber having an inlet and outlet connected to the outside while room air is circulated about the sealed chamber.
In addition to wood, coal, natural gas and electricity as heat sources, other hydrocarbon based materials also have long been in use. U.S. Pat. Nos. 500,765, 889,049 and 960,064 each suggest the use of alcohol as a fuel to burn and produce heat. In the '765 and '049 reference alcohol is burned in a cooking stove while the '064 reference sets forth an alcohol burning pocket heater.